The production of pharmaceutical grades of water using continuous deionization post-reverse osmosis.

Abstract

Continuous deionization (CDI) devices to purify water have recently become available. CDI and reverse osmosis (RO) equipment can form the key elements of water treatment trains that produce ultrapure water, without the need for the chemical regenerants associated with batch ion-exchange processes. CDI systems used as downstream polishers of RO product water have been found to be effective for the removal of trace ionic contaminants. Recently, CDI technology was extended, and devices are now capable of removing dissolved carbon dioxide without the requirement of pH adjustment. Examples from a number of installations are provided. CDI systems have been found to reduce the levels of total oxidizable carbon as well. Field experiences are provided and discussed. RO/CDI systems can be maintained to provide product water with low levels of bacteria and pyrogens. The results of a nine-month study of a system designed to produce pharmaceutical grade water are provided.